Demonstrating i-squared = -1

Demonstrating i-squared = -1
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2016-08-19 11:05
This example dynamically illustrates the geometric meaning of the imaginary unit i, visually showing that i-squared equals -1. It involves core mathematical concepts such as complex numbers, the imaginary unit, and the rotation of vectors with unchanged magnitude. GeoGebra commands like Vector, Mirror, Segment, and Point are used to construct the rotation of vectors, demonstrating the geometric effect of multiplying the imaginary unit by itself. Suitable for high school students to understand the geometric interpretation of complex number operations, or for teaching complex number calculations in calculus or linear algebra.

GeoGebra Commands & Parameters

  1. Vector((1, 0), (1, c)) → u
  2. Vector((1, 0), (1, b)) → v
  3. Mirror(v, xAxis) → v'
  4. Segment(A, B) → f
  5. Point(u) → C
  6. Point(v) → D
  7. Segment(A, C) → g
  8. Segment(A, D) → h
  9. Point(v') → E
  10. Segment(A, E) → i_2
  11. Point(g) → G
  12. Vector(F, G) → w
  13. Segment(H, I) → j
  14. Segment(J, K) → k
  15. Vector(L, M) → d
  16. Vector(P, Q) → l
  17. Segment(R, S) → m
  18. Segment(T, U) → n
  19. Vector(V, W) → p
  20. Segment(Z, A_1) → q
  21. Segment(B_1, C_1) → r
  22. Segment(D_1, E_1) → s
  23. Segment(F_1, G_1) → t
  24. Vector(H_1, I_1) → u_1
  25. Segment(J_1, K_1) → e
  26. Segment(L_1, M_1) → f_1
  27. Segment(N_1, O_1) → g_1
  28. Segment(P_1, Q_1) → h_1
  29. Segment(R_1, S_1) → i_1
  30. Segment(T_1, U_1) → j_1
  31. Segment(V_1, W_1) → k_1
  32. Segment(Z_1, A_2) → l_1
  33. Vector(B_2, C_2) → v_1
  34. Point(j) → K_2
  35. Vector(J_2, K_2) → w_1
  36. Point(j) → L_2
  37. Vector(L_2, M_2) → a_1
  38. Vector((1, 0), (1, (-a))) → b_1
  39. Point(b_1) → N_2
  40. Segment(N_2, A) → m_1